The fabrication of large structures may involve the performance of a large number of manufacturing operations on the structure, such as the drilling of a large number of holes. Conventional structures that require a large number of manufacturing operations include, for example, aircraft, missiles, ships, railcars, sheet metal buildings, and other similar structures. In particular, conventional aircraft fabrication processes typically involve the drilling of a large number of holes in wing sections of the aircraft to allow these sections to be attached to each other and to the airframe.
A variety of devices have been developed to facilitate drilling operations involving the drilling of a large number of holes. For example, U.S. Pat. No. 4,850,763 issued to Jack et al. discloses a drilling system that includes a pair of rails temporarily attached to an aircraft fuselage. A support carriage is slideably coupled to the rails and supports a drill assembly. A template attached to the aircraft fuselage provides an indication of the desired locations of the holes that are to be formed in the aircraft fuselage. As the carriage is moved along the rails, a locking mechanism (or trigger) interacts with the template to securely position the carriage for a subsequent drilling operation.
Although desirable results have been achieved using such prior art systems, there may be room for improvement. For example, prior art manufacturing tools may be undesirably heavy, particularly pneumatically-driven tools and other tools assembled from conventional components having individual housings and support bearings. Furthermore, at least some conventional pneumatically-driven tools do not provide precise controllability for performing manufacturing operations. Some pneumatic drill assemblies, for example, do not allow precise control of drill feed rate or rotational speed. Therefore, a need exists for an improved manufacturing apparatus that reduces weight and provides improved controllability for performing manufacturing operations on a workpiece.